A former undercover soldier said yesterday there is no evidence in intelligence reports that Martin McGuinness, Sinn Fein's chief negotiator, fired a weapon on Bloody Sunday.

Martin Ingram, the pseudonym of a member of the army's Force Research Unit, which ran agents in paramilitary groups, told the inquiry that he had access to hundreds of documents relating to the shootings of 13 unarmed Catholics.

"I saw documents relating to Martin McGuinness' activities on the day, both before and after the march," he said. "They related to what he was doing and who he was with. I saw none that suggested that he had a machine gun in his hand or fired a shot."

His evidence challenges that of a senior MI5 officer who says he was told by an agent in the IRA, codenamed Infliction, that Mr McGuinness confessed to having fired the first shot on January 30 1972.

Infliction made the allegation 12 years later, in 1984. Mr McGuinness denies the allegation but has agreed he was second in command of the IRA in Derry in 1972.

Mr Ingram said yesterday he believed the security services had up to 20 agents on the civil rights march. "I remember seeing documents that gave details of Mr McGuinness's movements indicating that he had been the subject of surveillance," he told the inquiry.

He added that they had received information from both Official and Provisional IRA sources that there was no intent to undertake military activity during the march.

Mr Ingram was not in Derry that day and Infliction was not an MI5 agent at the time, the inquiry has heard. Mr Ingram went to Northern Ireland with the army Intelligence Corps in 1981. He joined the Force Research Unit in 1982.

Documents he read "would leave the reader with the distinct impression that there were no shots fired at the troops prior to the troops opening fire", he said.

His impression, he added, was that "there had been no hostile fire and that the army had overreacted".

Mr Ingram said that he helped to debrief Frank Hegarty, an alleged IRA informer who was later murdered. He described Hegarty as a "senior man in the IRA" who was "emphatic when he told me that there was no action planned by the stickies [members of the Official IRA] on Bloody Sunday".

However, he admitted that he had probably not seen MI5 documents when he was in the Intelligence Corps.